1. Field of the Invention
The present invention relates to a system and process for composing an image data for use in image forming apparatus. For example, the present invention is used for forming a color print composed from a polychrome original and monochrome original.
2. Description of the Prior Art
In a color copying apparatus or the like, the image of a polychrome original (color original) is conventionally separated into the three primary colors of red, green an blue. A set of primary color items of image data corresponding to each pixel are then stored in memories for the different primary colors. It is difficult, however, to store monochrome image (binary image) data, such as character image data, in such memories along with polychrome image data because in the difference of storage modes thereof. Accordingly, there is a need to provide, independent of the memories for storing the primary color items, a memory for independently storing the monochrome image data in order to superimpose the monochrome image on a polychrome image printed out (see, for example, U.S. Pat. No. 4,516,139).